At first I thought I was going mad but as it turns out, the Numista swap machine is losing my messages and not sending them on. I think it is when I confirm a swap or accept another member's offer and when I do, the site then gives me a box to send a message to my swap partner so I give them my address and ask them to send theirs to me. The next thing I hear is the member messaging me to say 'send me your address' and I think this idiot must be blind but when I check the swap conversation there is nothing there and nothing in my sent items. It is as if the message I sent does not exist and yet I know I wrote the information in the message box, pressed send and the site confirms that my message was sent. I don't know how you are going to debug this but it is driving me mad and I suspect I am not the only one.
Just because you can't see it ... doesn't mean it isn't there - Anon.